[ruby-core:112233] [Ruby master Bug#19418] Checking if a date in an open date range times out when the range starts after the test date

Issue #19418 has been updated by zverok (Victor Shepelev).


[Range#include](https://docs.ruby-lang.org/en/3.1/Range.html#method-i-include-3F) basically iterates throughout the range and compares every value with the target value; it requires only two methods: `value.succ` and `value.==`, and never uses anything else. Therefore, it is infinite iteration when nothing was found.

This is a generic implementation that works for all classes, not only for `Date`. 

Simplest test:

```ruby
V = Struct.new(:val) do
  def succ = V.new(val+1) # this will implement iteration
end

(V.new(2)..).include?(V.new(1))
# -- hangs forever
```

The `include?` though redefined to behave like [Range#cover?](https://docs.ruby-lang.org/en/3.1/Range.html#method-i-cover-3F) for some range types: namely, numbers and strings. (So, your check of `(2..).include?(1)` doesn't prove "something wrong with Date", it proves "something 'wrong' (specialized for historical reason) with numbers".)

`cover?` is the right method to check "if something is inside the range":
```ruby
require 'date' 
((Date.today + 1)..).cover?(Date.today) #=> false, immediately
```

BTW, just discovered the 3.2 tries to lessen the confusion by prohibiting `include?` on infinite ranges (though it is never mentioned in `NEWS`, hm):
```ruby
RUBY_VERSION
# => "3.2.0" 
require 'date'
((Date.today + 1)..).include?(Date.today)
# in `include?': cannot determine inclusion in beginless/endless ranges (TypeError)
```

----------------------------------------
Bug #19418: Checking if a date in an open date range times out when the range starts after the test date
https://bugs.ruby-lang.org/issues/19418#change-101655

* Author: wilhelmsen (Hallgeir Wilhelmsen)
* Status: Open
* Priority: Normal
* ruby -v: 3.1.3
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN
----------------------------------------
`
require 'date'
((Date.today + 1)..).include?(Date.today)
`

is expected to return `false`. It never return a value, as like it is in a never ending loop.


`((Date.today)..).include?(Date.today)`

however, returns `true` right away.

`(2..).include?(1)`

also returns false, as expected.


I.e. this seems to be a date issue and not a range issue, and it seem to happen when the start date comes after the date to check for.



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